Drill mechanism



R. K. JEFFREY DRILL MECHANISM 3 Sheets-Sheet 2 Filed Sept. 24, 1930ii/I0 Egg . ll- .E v

Feb. 11,1936. R. K RE 2,030,636

DRILL MECHANISM Filed Sept. 24, 1930 5 Sheets-Sheet 5 [NVENTOR Robe/ff1. Jeffrey.

a MA a Patented Feb. 11, 1936 UNITED STATES Zar PATENT OFFIE DRILLMECHANISM Robert K. Jeffrey, Columbus, Ohio, assignor to The JeffreyManufacturing Company, Columbus, Ohio, a corporation of Ohio ApplicationSeptember 24, 1930, Serial No. 484,190

19 Claims.

- charges,

According to the present invention means are provided to retract orwithdraw the auger without reversing its direction of rotation. To thisend the prime elements of the new mechanism are a rotatinglongitudinally displaceable screw shaft to which the auger isattachable, a feed nut rotatable in the same direction as the screwshaft, but at greater speed, so as to feed the shaft, clutch means toconnect the nut with a rotary drive element, and means to arrestrotation of the nut to withdraw the shaft. The .clutch is provided witha non-rotating shipper member which, when moved in one direction,engages the clutch elements, and, when moved in. the opposite direction,comes into frictional contact with a braking surface associated with thenut so as to arrest rotation of the nut. Actuating means are providedfor the shipper member for moving the latter to the desired position andretaining it in such position and the clutch loading movement isyieldingly effected.

In addition to the more general features just mentioned, the inventionincludes subsidiary features as will hereinafter appear.

An illustrative embodiment of the invention is shown in the accompanyingdrawings, in

which:

Figure 1 is a side elevation of the complete drilling mechanism, withthe floor engaging means shifted 90 out of normal position in order toshow the detailed construction thereof.

Figure 2 is a plan view of the device shown in Figure 1.

Figure 3 is a longitudinal section the line 3-3 of Figure 2.

Figure 4 is a sectional view taken along the line 4-4 of Figure 3.

Figure 5 is a sectional view taken along the li-ne155 of Figure 3.

Figure 6 is a sectional view taken along the line 66 of Figure 2.

Figure '7 is .a vertical section of the lower end of the post showingone means of adjusting the height thereof. 7

Figure 8 is .a section taken along the line 8-8 taken along of Figure 3,and is illustrative of one form of auger mounting means.

Figure 9 is a sectional view of a modified form of auger mounting means.

Figure 10 is a section taken on the line lill ii 5 of Figure 9.

Figure 11 is a diagrammatic view of the drilling mechanism set up foroperation.

Referring specifically to the drawings, in which like numbers indicatelike parts, and particularly 10 to Figure 11, there is provided a postBl having a roof engaging member I 06 and an adjustable floor engagingmember H l. A drill supporting member 85 adapted to be slidably fixed tosaid post by means of a bearing member 36 carries the 15 motor casing towhich is attached, by bolts 26, the gear casing 25, which carries all ofthe gearing and clutch mechanism. The auger or drilling bit 15 isdetachably held by a socket it fixed to the end of a feed screw ll,which is operatively connected to a motor l8 within a motor casing whichcomprises a frame 29 having bearings 22 at one end thereof and acommutator housing 2| having bearings 23 at the other end thereof, thehousing having fixed thereto a switch 25 housing 19, as shown in Figure3. An armatureshaft 24 .is mounted in the bearings 22 and 23. Thecasings 1'9, 20, and 2 l thus formed and joined, make a unit which isairtight in order to eliminate the danger of gas explosions, while theuse of an electric motor is not essential, it is desirable.

Referring now more particularly to Figures 1, 2 and 3, a journal bearing21 is cast integral with the topwall of the field frame 20 and isprovided with an elongated bushing 28 within which is rotatably mounteda driving quill 29 by means of which the feed screw I! is supported inthe bearing 27. The said quill and feed screw are splined together andthe latter derives driving power from the former. A gear 30 keyed to thequill 29 meshes with a pinion 3| which is fixed to the armature shaft 24of the motor I8. Since the feed screw will extend rearwardly of thebearing 21, a pipe guard 32, screw threaded to said bearing, is providedto prevent injury to the operator.

A sleeve 33 is positioned immediately in advance of the quill 29,partially Within the gear casing 25, and partially within a nut casing49, the latter being disposed in front of the former and fixed to thesleeve. the feed screw I? and its bore is slightly larger than thediameter of said feed screw; in order that it may be rotatablysupported, ball bearings 35 are provided at one end thereof between theThe sleeve 33 surrounds outside of the quill 29 and laterally extendingannular flange 35, and at the other end thereof by ball bearings 3!fitted into the bore of a bearing 58 of the gear casing 25. A cap orgudgeon 39 closes the end of the bearing and holds the a gear .45 whichmeshes with a pinion 46 fixed to the outer end of the armature shaft 24.

A shipper ring or collar 4'! provided with a flange 48 having a clutchlining 49 fixed to its outer face encircles the elongated hub 44 of thegear 45. The shipper ring is provided with thrust members positioned ateither side of a radial flange formed at the free end of hub 44, therebeing a plain thrust ring at the left of the flange and a ball bearingassembly at the right thereof, Fig. 3.

Thus the gear may be shifted to the left through the shipper member witha minimum of friction, elimination of friction in moving the gear to theright being inessential, as will appear. The gear 45 is provided with aplate center 50 to the outer face of which is fixed a clutch lining 5!.A lever in the form of a yoke, 52 is pivoted at its upper end to thegear casing 25 on a pin 53, and is connected to the shifter collar 41 bypins .or trunnions- 54, being adapted to be swung longitudinally of thesleeve 33 in one direction in order to operatively connect the gear 45to the said sleeve through plate 4| and thereby rotate the nut casing45, or when shifted in the opposite direction to engage the clutchshifter collar with flange 427and thereby arrest rotation of sleeve 33and nut casing 45, the collar being held against rotation by pins 54.

The nut 34, as shown in Figures 3 and 5, is made in two parts, each partbeing provided at one end thereof with a pair of cars 55'piercedby'sruitably aligned apertures. The nut casing 40 comprises acylindrical outer wall 55 and is provided with inwardly extendingflanges 5'17 and 58 which form a pocket 59. The said flanges are piercedby diametrically disposed aligned apertures adapted to receive pins 55and BI which are fixed to the nut casing 45! against longitudinalmovement by shoulders 62 and cotter pins 63. .The

pins 65 and 5% extend through apertures in the ears 55 of each half ofthe nut. The ears 55 being positioned between flanges 51 and 58,longitudinal movement of the nut relative to the nut casing isprevented, and rotary movement of each half of the nut about the pins 55and Si is permitted. Encircling the two halves of the nut in order tohold them in engagement with the feed screw is a feed nut sleeve 55which is provided at its outer end with a spring pressed detent 55 ofusual construction, adapted to fit a groove 61 cut in the periphery ofthe nut. This arrangement prevents longitudinal movement of the sleeverelative to the nut except when it is desiredrto remove the sleeve inorder that the nut may be disengaged from the feed screw. Springs 58 arewound around the pins 59 and ti and the ends 59 abut against the outerwall of the pocket 59, while the ends '95 extend between the nut halves.The springs are so arranged that they exert an outwardly directed forceagainst each part of the lows the parts to be disassembled.

nut and the tendency is to move each half about its pivot to inoperativeposition to cause the disengagement from the feed screw.

Referring more particularly now to Figures 3 and 4, the yoke 52comprises two identical cast- 5 ings, each having a boss H at theiruppermost portion for pivotal connection to the pin 53 and to maintainthem in properly spaced relationship. Similar bosses 12 are provided attheir lowermost portions and by means of a bolt 13 1 the two members areclamped together. Depending downwardly from the bosses 12 are lugs. E4,each provided with an aperture inwhich is journaled a trunnion pin 15 ofa nut 15. A screw threaded shaft El provided with a hand wheel 8! 1extends through a bearing 19 of the gear casing and into the nut '15. Aspring cup 8| abuts a shoulder 52 'of the shaft ET and is heldthereagainst by a spring 83 interposed between said cup and gear case,thereby preventing longitu- 2 din-a1 non-rotative displacement of theshaft E1 relative to the gear case except under certain conditions laterto be described.

An arcuate flange 84, the periphery of which extends 180, is castintegral with the motor cas- 2 ing 20. A drill supporting member 85having a bearing 85 adapted to be fixed to the post 8'! is also providedwith an arcuate flange 88, the pe riphery of which extends through 180.It will be noted in Figure 6 that the flanges 84 and 88, 3 when inassembled relation, lock with each other, and thereby'support the drillmechanism on the post.

In order that the parts may be held in fixed relation, there is provideda screw shaft 82, con- 3- centric with the arcuate flanges,

extending through a bearing sleeve of member 5'5. into a screw threadedaperture of a boss 96 formed on the motor casing 25. shaft 89 is a handwheel 92 which when rotated inwardly securely clamps the casting 85 tothe motor casing, and when rotated outwardly unti. the shaft 89 isentirely clear of the boss 91, al-

The drill mechanism is adjustable on the post 4 8! without disassemblingthe parts. The bearing 85 which carries the flange 58 is provided witha'pair of apertured lugs 93 through which extends a pin 94. A lever 555having a pawl nose 95 is pivoted on the pin Mand the nose 9% 'is '5engageable with the teeth 9 on said post. A spring 98 is interposedbetween the boss 99 of the bearing 85 and an offset I55 of the lever 95,and tends to keep the nose 95 engaged withtheteeth 91. A boss IE2! isprovided on the bearing 85, and 5 a clamping bolt 152 having a handleH33 prevents vertical movement. of the bearing on the post.

In order that the entire post and drill will be in balanced relation,the floor and roof engaging 6 means are ofifset as indicated withreference to the floor engaging means in Figure 1. Thereof engagingmeans comprises an arm- I54 clamped to the post by the bolt E55 and isprovided with a pointed member Hit, The floor engaging means 6 isadjustable to different heights and comprises an arm I51 clamped to thepost by a bolt liiand provided with a bearing member 559 inside of whichis slidably mounted a jack pipe H5. As shown in Figure '7, the bearingmember it??? is 7 provided with a pair of apertured lugs as at I48 7through which extends the pin I i-i. A lever l4? having a pawl nose M3is pivoted on the pin 9 4iand the nose I43 is engageable with teeth M4on said jack pipe. A spring H45 is interposed be- *7 On the outer end ofthe 40 tween bearing member I 09 and an offset "I45 of lever E42, andtends to keep the nose I43 engaged with the teeth I44. A boss I4! isprovided on the bearing IE9 and a clamping bolt I418 having a handle I49prevents vertical movement of the bearing on the post. Further adjustingmechanism is provided by the screw jack III mounted within the jack pipeI It and having a'hand wheel I I2 which is held against the longitudinalmovement away from the jack pipe by means of a spring-pressed pin I I3engaging a shoulder Il turned on the jack pipe. The screw jack III isprovided with a keyway extending throughout the length thereof and a keyII5 formed in the bore of the jack pipe III] prevents rotation of saidscrew jack when the hand wheel I I2 is rotated. Therefore, by rotationof said hand wheel the screw jack will be moved longitudinally of thejack pipe to adjust the overall length of the post mounting.

One form of auger socket is shown in Figures 2, 3 and 8 and comprises asocket portion H6 adapted to fit over the end of the feed screw I7 andrigidly fixed thereto by rivets Ill. The opposite end of the socket isprovided with a pocket of polygonal cross section and is adapted toreceive the tail piece I I8 of the auger. When transporting the drillfrom one place to another or in auger from its connection with the feedscrew. In order that this may be done the tail piece H8 of the auger isprovided with a transversely extending groove H9 which when assembledwith the socket is in partial register with a suitable aperture lZil insaid socket, through which extends a pin IZI said pin being sopositioned that it will hold the two parts in working relation Byrotation of the pin IBI, a flat portion l22 will be brought intoregister with the said tail piece of the auger to permit removal of theauger.

A second form of auger socket is shown in Figures 9 and 10. The tailpiece II8 of the auger is riveted in said socket which at its other endis provided with internal keys I23 cast integral therewith and engagedin key-ways of screw H to prevent rotation of the feed screw and socket.A ring I 24 is positioned around the outer periphery of said socket andis provided with a pin I25 adapted to be inserted through an apertureI26 in the socket wall and into a radial recess I2! in the feed screw.The said ring is suficiently large to permit removal of pin I25 fromsaid recess so that the socket may be disengaged from the end of thefeed screw. A spring I28 is seated in a notch 29 in the socket and haslaterally extending arms E36 which engage the inner surface of the ringto hold the ring I2 1 in the position shown to prevent accidentaldisengagement of pin I25 from the recess I21, but allowing removal ofsaid pin from said recess upon forced flexure of the spring. Lugs I3Iare cast integral with the socket to prevent longitudinal movement ofthe ring I2 5 relative to the socket. The use of this form of socketpermits removal of the feed screw from its association with the otherparts. To accomplish this, the socket is removed from the end of thefeed screw and the sleeve 55 is removed from the nut 34 whereby eachhalf of said nut is rotated by its associated spring about its pivotalconnection with the nut casing M3 to disengage the threads of the nutfrom the feed screw which may then be pulled out the rear end of theguard pipe 32.

The drill mechanism is thus removably attached to the post andvertically adjustable thereon. It may be adjusted about a horizontalpivot or the entire post and drill may be adjusted about the floor androof engaging means in order to place the drill in position for thedrilling of holes in various angles to the coal face.

When it is desired to take down or set up the parts of the drill inworking relation, the post is inverted to place the floor engaging meansat the top in such a position that the flange 88 is in line with thegroove of the motor casing when the post is rotated about the center ofthe flange 88 so that said flange is engaged in a groove formed by theflange 84. When the post is in an upright position with the connectionmade as described, the parts are in assembled relation.

In operation, after the post is properly set up with relation to thecoal face, the drill mechanism may be raised by lifting the drillmechanism and in so doing allowing the pawl nose 9% to slide over theteeth 91, and the drill mechanism may be lowered by lifting the lever todisengage the pawl nose 96 from the teeth $1. The clamping screw I52 maybe tightened to securely hold the drill in properly adjusted position-on the post.

By means of the novel arrangement of parts, the feed screw rotates theauger at the desired cutting speed and it may be fed in eitherdirection, forwardly at a relatively slow feeding speed and reversely ata relatively high withdrawal speed. It will be noted that when the gear@5 is shifted to the left by means of the shifter collar '41, referringto Figure 3, a contact is made between the plate center 59 on the gearand the flange M, the spring 83 acts as an abutment and 1 should thecutting become too hard for feeding at the usual feed of fifty inchesper minute, the spring will be compressed which allows slipping of theclutch. When the shifter collar is moved in the opposite direction theclutch as will be engaged to prevent rotation of the nut, and since thefeed screw is rotated clock-wise and the threads are left handed, thefeed screw will be moved in a reverse direction. When this operation isperformed the hand wheel 88 abuts the boss I9. A spring could beinterposed between the boss 19 and the hand wheel 83, but it has beenfound unnecessary to satisfactory operation since the feed screw willnot be overloaded when withdrawing the auger.

The plate 5!] with its lining or face 5| constitutes one element of afriction clutch the other element of which is the friction plate 4!. Ina similar manner the plate 48 and lining or face 49 constitute oneelement of the other friction clutch, the other element of which is thefriction plate 42. When the manually operable mech anism comprising thewheel Gil and the screwthreaded rod l8 holds the clutch elements d8, 49and 50, 5| midway between the clutch elements ll and 42 out of contactwith both, the

drill will be retained in neutral position so far as feed is concerned,although it may continue to rotate to cause the convolutions of thedrill, as shown at I5 in Figure 11, to convey the cuttings rearwardlyout of the previously drilled hole.

It will thus be seen that the threaded bar El may be continually.rotated in the same directicn and while being so rotated the drill maybe fed forwardly, the forward feed may be stopped to finish the bottomof the drill hole and to remove some of the cuttings from the hole, andthen fed backward to remove the drill from the hole while cleaning outremaining cuttings from the through the housing and for retractiblemovement in'the opposite direction through the housing, and drivingmeans connected through a train of gearing to the tool to impartrotative and reciprocal movements to the tool. Such train of gearingincludes clutch means controlled by a manually movable member 52 movableinto selective positions whereby the clutch means may be alternativelyactuated to effect feeding movement of the tool when the member 52 is inits left-hand position as viewed in Fig. 3, to retain the tool neutraland rotative when the member 52 is in its central position, and toeffect retraction of the tool when the member 52 is in its right-handposition.

When the motor I8 is operating, the drilling tool is being driven in aclockwise direction as viewed from its rear end. When the lever 52 ismoved to the left as viewed in Fig.3 the nut 34 will also be rotated ina clockwise direction but at a higher speed as determined by the gearratios at 3!, 30 and 46, 35, the pinion Mi being of greater diameterthan the diameter of the pinion 3i, and the diameter of the gear 45being less than the. diameter of the gear 30, as shown in Fig. 3. Thedifferential betweenthe clockwise rotation of the left-hand threads I!and the clockwise rotation of the'nut 34 will result in a slow forwardfeeding movement of the drilling tool.

When the lever 52 is in central or neutral position the nut 34 is freeto rotate with the screwthreaded rod 'l'i and consequently the drillwill continue to rotate in a clockwise direction without being fed orretracted. When the lever 52 is moved to itsright-hand position the nut34 will be held stationary by the engagement of the clutch elements 43,49 and 42', the gear 50 being free to rotate relatively to the elementQ8 by reason of the ball thrust bearing shown in Fig. 3. When the nut 34is thus held against rotation the clockwise rotation of the left-handedthreads il will effect a relatively quick retraction of the drill fromthe hole while cleaning'it of cuttings therein.

The ratio of reduction between pinion 3| and gear 30 is greater thanthat between pinion i5 and gear 45. In fact, the motor revolving at 3000R. P. M. will rotate the gear 30 at 600' R. P. M. and the gear 45 at 800R. P. M. Since the difference in R. P. M. is 200 and the left handedthreads on the feed screw are four per inch, the auger will be fed intothe .coal at the rate of fifty inches per minute. The reverse feed willbe three times as fast, or one hundred and fifty inches per minute.Experimentation in actual use has proven the above described drill mech-I claim:

1. In apparatus of the class described, a longitudinally displaceablescrew shaft, means to rotate said shaft, a nut. engaging the threads.

of said shaft, means to rotate the nut in the same direction as theshaft andat a speed greater than that of the shaft to cause longitudinaldisplacement of the latter in one direction, and brake means forarresting rotation of the nut'during rotation of the shaft to causedisplacement of the shaft in the other direction.

2. In apparatus of the class described, a longitudinally displaceablescrew shaft, means to rotate said shaft, a nut engaging the threads ofsaid shaft, means including a friction clutch to rotate the nut in thesame direction as the shaft and at a speed greater than that of theshaft to cause longitudinal displacement of the latter in one direction,brake means for arresting the rotation of the nut during rotation of theshaft to cause displacement of the shaft in the other direction, andmeansto control said clutch, said last named means being operable toengage the clutch and hold it in engaged disposition.

3. In apparatus of the class described, a longitudinally displaceablescrew shaft, means to rotate said shaft, a nut engaging the threads ofsaid shaft, means including a friction clutch to rotate the nut in thesame direction as the shaft and at a speed greater than that of theshaft to cause longitudinal displacement of the latter in one direction,brake means for arresting the last named means'being operable to engagethe clutch and hold it yieldingly in engaged disposition.

4. In apparatus of the class described, a longitudinally displaceablescrew shaft, means to rotate said shaft, a nut engaging the threads ofsaid shaft, a gear mounted concentrically with said shaft and rotatableindependently thereof, cooperating clutch elements between the gear andnut whereby the former is adapted to drive the latter, means forengaging said clutch elements, means to rotate the gear and thereby thenut in the same direction as the shaft and at a speed greater than thatof the shaft to displace the latter longitudinally in one direction, andbrake means for arresting rotation of the nut during rotation of theshaft to cause displacement of the rotate said shaft, a nut engaging thethreads of 7 said shaft, a, rotatable sleeve freely surrounding theshaft and secured to the nut, a gear mounted concentrically with theshaft, a clutch comprising driving and driven elements in connectionwith the gear and sleeve respectively, means to rotate the gear in thesame direction as the shaft and at a speed greater than that of theshaft, means operable to engage the clutch elements and hold them inengaged relation to cause rotation of the nut at the speed of the gearand thereby efiect longitudinal displacement of the shaft in onedirection, and brake means for arresting rotation of the nut when theclutch elements are disengaged whereby continued rotation of the shafteffects displacement of the shaft in the other direction.

6. In apparatus of the class described, a longitudinally displaceablescrew shaft, means to rotate said shaft, a nut engaging the threads ofsaid shaft, a rotatable sleeve freely surrounding the shaft and securedto the nut, a gear mounted concentrically with said sleeve, opposedfriction surfaces on the gear and sleeve, means for axially displacingthe gear to engage and disengage said surfaces, means to rotate the gearin the same direction as the shaft and at a speed greater than that ofthe shaft, the nut being rotated at the speed of the gear uponengagement of the friction surfaces to displace the shaft in onedirection, and brake means for arresting rotation of the nut when thefriction surfaces are disengaged whereby continued rotation of the shaftefiects displacement of the shaft in the other direction.

7. In apparatus of the class described, a longitudinally displaceablescrew shaft, means to rotate said shaft, a rotatable sleeve freelysurrounding said shaft, a nut fixed to said sleeve and engaging thethreads of said shaft, a pair of spaced radial flanges on said sleeve, agear rotatably mounted on said sleeve between said flanges, anon-rotating shipper member mounted in connection with the gear to shiftthe latter axially, said gear having a friction surface adapted toengage one of the flanges to drive the sleeve and nut when the gear isshifted in one direction, said shipper member having a friction surfaceadapted to engage the other of said flanges when the gear is shifted inthe other direction, and means to drive said gear in the same directionas the shaft and at a speed greater than that of the shaft.

8. In apparatus of the class described, a longitudinally displaceablescrew shaft, means to rotate said shaft, a rotatable sleeve freelysurrounding said shaft, a nut fixed to said sleeve and engaging thethreads of said shaft, a pair of spaced radial flanges on said sleeve, agear having an elongated hub rotatably mounted on said sleeve betweensaid flanges, a non-rotating shipper ring in connection with said hub toshift the gear axially, said gear having a friction surface adapted toengage one of the flanges to drive the sleeve and nut when the gear isshifted in one direction, said shipper ring having a friction surfaceadapted to engage the other of said flanges when the gear is shifted inthe other direction, and means to drive said gear in the same directionas the shaft and at a speed greater than that of the shaft.

9. In apparatus of the class described, a longitudinally displaceablescrew shaft, means to rotate said shaft, a rotatable sleeve freelysurrounding said shaft, a nut fixed to said sleeve and engaging thethreads of said shaft, a pair of spaced radial flanges on said sleeve, agear having an elongated hub rotatably mounted on said sleeve betweensaid flanges, said hub having a radially projecting portion spaced fromthe gear, a nonrotating shipper ring having an internal circumferentialgroove in which the radially projecting portion of the hub is engaged,said gear having a friction surface adapted to engage one of the flangesto drive the sleeve and nut when the gear is shifted in one direction,said shipper ring having a friction surface adapted to engage the otherof said flanges when the gear is shifted in the other direction, andmeans to drive said gear in the same direction as the shaft and at aspeed greater than that of the shaft.

10. In apparatus of the class described, a longitudinally displaceablescrew shaft, means to rotate said shaft, a rotatable sleeve freelysurrounding said shaft, a nut fixed to said sleeve and engaging thethreads of said shaft, a pair of spaced radial flanges on said sleeve, agear having an elongated hub rotatably mounted on said sleeve betweensaid flanges, said hub having a radially projecting portion spaced fromthe gear, a shipper ring having an internal circumferential groove inwhich the radially projecting portion of the hub is engaged, said gearhaving a friction surface adapted to engage one of the flanges to drivethe sleeve and nut when the gear is shifted in one direction, saidsln'pper ring having a friction surface adapted to engage the other ofsaid flanges when the gear is shifted in the other direction, a shiftinglever pivoted to said shipper ring and restraining the latterj againstrotation, and means to drive said gear in the same direction as theshaft and at a speed greater than that of the shaft.

11. In an apparatus of the class described, a longitudinallydisplaceable screw shaft, means to rotate said shaft, a rotatable sleevefreely surrounding said shaft, a nut fixed to said sleeve and engagingthe threads of said shaft, a pair of spaced radial flanges on saidsleeve, a gear having an elongated hub rotatably mounted on said sleevebetween said flanges, said hub having a radially projecting portionspaced from the gear, a nonrotating shipper ring having an internalcircumferential groove in which the radially projecting portion of thehub is engaged, said gear having a friction surface adapted to engageone of the flanges to drive the sleeve and nut when the gear is shiftedin one direction, said shipper ring having a friction surface adapted toengage the other of said flanges when the gear is shifted in the otherdirection, a shifting lever pivoted, to said shipper ring andrestraining the latter against rotation, a self-locking screw and nutunit for swinging said lever, and means to drive said gear in the samedirection as the shaft and at a speed greater than that of the shaft.

12. In apparatus of the class described, a longitudinally displaceablescrew shaft, means to rotate said shaft, a nut on said shaft, a rotaryelement on said shaft, means to drive said rotary element in the samedirection as the shaft and at a speed greater than that of the shaft,clutch means between said rotary element and said nut, and operatingmechanism for said clutch means comprising a self-locking screw and nutunit.

13. In apparatus of the class described, a longitudinally displaceablescrew shaft, means to rotate said shaft, a nut on said shaft, a rotaryelement on said shaft, means to drive said rotary element in the samedirection as the shaft and at a speed greater than that of the shaft,clutch means between said rotary element and said nut, and operatingmechanism for said clutch means comprising a self-locking screw and nutunit and a spring receiving the reaction of said unit.

14. In apparatus of the class described, a longitudinally displaceablescrew shaft, means to rotate said shaft, a nut on said shaft, a. sleevefreely rotatable on said shaft and fixed to said nut, a rotary elementon said sleeve, a clutch comprising cooperating parts in connection withsaid nut and rotary element respectively, means to shift said rotaryelement to engage said parts, and means to drive the rotary element inthe same direction as the shaft and at a speed greater than that of theshaft.

15. In apparatus of the class described, a longitudinally displaceablescrew shaft, a gear splined on said shaft, a nut engaging the threads ofsaid shaft, a sleeve freely rotatable on said shaft and fixed to saidnut, a 'geaiiro-ta'table on said sleeve, a drive shaft, pinions on saiddrive shaft respectively engaging the gears to drive the same, cooperating clutch elements on said rotatable gear and sleeve, and means foraxially displacing said revoluble gear to engage said clutch elementsand drive the nut, the drive ratio to said nut being greater than thatto said shaft. 7

16. In apparatus of the class described, a longitudinally displaceablescrew shaft, a gear splined on said shaft, a nut engaging the threads ofsaid shaft, a gear freely rotatable on the axis of said shaft, frictionclutch means operable to connect the last named gear and nut, brakemeans operable to hold said nut against rotation upon disengagement ofsaid friction clutch means, a power shaft, and pinions on said powershaft respectively engaging the gears to drive the same, the drive ratioto said nut being greater than that to '3 said shaft.

17. In apparatus of the class described, drill mechanism and housingmeans therefor, said mechanism comprising a rotatable screw shaftextending through said housing and longitudi- V nally displaceablerelative thereto, a gear splined on said shaft, a nut engaging thethreads of said shaft, a gear freely rotatable on the axis of saidshaft, friction clutch means operable to connect said last named gearand nut, a motor casing in connection with said housing means, an

mechanism and housing means therefor,- said mechanism'comprising arotatable screw, shaft extending through said housing and longitudinally displaceable relative thereto, a gear splined on said shaft, a nutengaging the threads of said shaft, a gear'freely rotatable onthe axisof said shaft, friction clutch means operable'to connect said last namedgear and nut, brake means operable to hold said nut against rotationupon disengagement of said friction clutch means, a motor casing inconnection with said housing means, an electric motor in said casingwith its armature shaft parallel to said screw shaft, and pinions onsaid armature shaft respectively engaging the gears to drive the same,the drive ratio to said nut being greater than that to said shaft.

19. In a mining drill, the combination of a housing, a threaded tooloperatively arranged in said housing for longitudinal movement in onedirection through the housing and for retractible movement in theopposite direction through said housing, a driving means, a train ofgearing including clutch means adapted to be actuated by said drivingmeans for imparting rotative and reciprocal movement tosaid tool, acontrollable means for such clutch means, said controllable meansincluding a manually movable member, movable into selective positionswhereby the clutch may be alternatively actuated to impart reciprocalmovement to said tool when such member is in one position, in anotherposition to retain the tool neutral and rotative and in another positionto impart to the tool reciprocal movement in the opposite direction.

ROBERT K. JEFFREY.

